I dont think there are any rules, its just that what makes this special is that once you post something on the blockchain its on there forever. Feel free to post whatever you want just make sure you know what youre doing when you do it

Im not entirely sure how deleting a post works though on the steemit blockchain, because you only have so long to delete it. you can check everything though here https://steemd.com/dtube/@facebookx

And now that ive checked it i guess you do have until the timer is up to delete content. But once it locks in all you can do is edit.